It's a Finnish word that, according to Finland's tourism website, typifies the enduring spirit of all Finns: "stoic determination, hardiness, courage, bravery, willpower, tenacity and resilience."
It's also the word Houston Astros pitching coach Brent Strom used with his pitchers in a meeting before Game 4 of the American League Championship Series on Tuesday. The message he delivered might be the difference-maker in this series, because over the following two days, Astros pitchers held the previously red-hot Boston Red Sox offense to just three runs -- and the Stros are returning to Houston with a 3-2 series lead.
"I talked to them about getting out of their comfort zone and taking it a step further," Strom told ESPN after the Astros' 9-1 win in Game 5 on Wednesday. "People laugh at me about this, but 'sisu' harkens back to when the Soviets invaded Finland and [the Finnish] were outnumbered in men, 3 to 1, 400 airplanes to 32, 600 tanks to 27. And they held them to a stalemate."
Strom wanted his young pitchers to rise to the occasion, even when it seemed everything was working against them. The Astros had given up a whopping 21 runs in Games 2 and 3, and the series seemed to be slipping away.
"I've been very blessed with the [Justin] Verlanders and the [Gerrit] Coles and the [Dallas] Keuchels and all these guys that have been there, done it," Strom said. "This is a whole new group right now, and I just asked them to dig a little deep.
"The bullpen was taxed. We were beat up a little. But they stepped up in a big way."
Strom got 7 innings of scoreless baseball from his pen in Game 4, then got the performance of the series in the form of lefty starter Framber Valdez, who went eight innings in Game 5. Valdez took "sisu" to heart after a bad start in Game 1, when he lasted just 2 innings.
"I had a really ugly outing," Valdez said through an interpreter. "I felt humiliated after that first outing, and I set my mind on not letting that happen again. I did everything I could to work as hard as I possibly could to come back and have success in this outing."
Boston managed just three hits off of Valdez. Red Sox manager Alex Cora called Valdez's sinker "unreal."
"Walks have been an issue in the past, but we saw him throw a lot of strikes today," Strom said of Valdez. "They had a tough time getting the ball out of the infield. When you throw ground balls, sometimes the cost of one out equals two."
In Valdez's only moment of trouble, it wasn't Strom who went to the mound to talk to him; it was Astros manager Dusty Baker. With two on and no outs in the fifth inning and a 1-0 score, this would be the key moment.
"I didn't say a whole bunch to him," Baker recalled. "It was kind of like you call a 20-second timeout in basketball and try to take the air out of the game. That was a 20-second timeout that probably took 15 seconds."
On the next pitch, Valdez threw a sinker to Hunter Renfroe to induce a 6-4-3 double play. A moment later, he got Alex Verdugo to ground out. The threat -- and, soon enough, the game -- was over.
Strom believed it was either just the "first or second time" all season Baker went to the mound without pulling his pitcher.
"Whatever Dusty said to him was better than what I could have done," Strom said with a smile. "I just pray a lot."
Strom reiterated to Valdez before the game, as he had in their pitchers meeting the night before, that he needed to get ahead in the count.
Through the first four games of the ALCS, the Astros averaged 40 pitches per game in hitter's counts. On Wednesday, Valdez threw just 14.
"In the first game, even in our place, he was amped up," Strom said of Valdez. "First time in a playoff game with [fans]. It was like spring training last year."
Even Cora noticed the difference -- although he didn't mention "sisu."
"They made some adjustments," he said. "There's a few things they're doing that they didn't do in the first three games, and we just got to be ready."
Throwing strikes is No. 1 on that list. It was the one bit of technical advice Strom gave his pitchers after asking them to dig deep.
"This is a very good Red Sox offense, which controls the strike zone very well," Strom said. "J.D Martinez is a great leader of them. We had to take the strike zone back."
Strom pointed at one pitch, well before the Renfroe double play on Wednesday, which indicated to him they were in for a different night from their starter. In the bottom of the first, Valdez threw seven pitches to Red Sox leadoff manEnrique Hernandez. That seventh, on a full count, was a beauty of a sinker on the inside portion of the plate. Hernandez was caught looking.
In the dugout, Strom sighed in relief. The Red Sox had been scoring so much, so early in this series. He knew the last thing Houston needed was a free pass to the first Red Sox batter.
"A strikeout rather than a walk," Strom said. "Maybe it's just me, but sometimes you go, 'Oh s---, here we go again.' [But] that changed the narrative a little bit."
Perhaps it changed in that meeting room, at a time when the Astros' pitching staff had to reset itself or start making offseason vacation plans. The feeling at Fenway Park after Game 3 was that the series might not go back to Houston. Instead, the Astros are one win from another World Series appearance with two home games waiting for them.
"It's just about determination and grit, going beyond your comfort zone," Strom said. "That's the word they used.
Schwarber's error sparks big 6th from Astros
Michael Brantley reaches first base on an error by Kyle Schwarber, which set the table for Yordan Alvarez and Yuli Gurriel to each hit an RBI double. Jose Siri then hits an RBI single to give Houston a 6-0 lead.